Intracellular Compartments and Transport Flashcards
Endoplasmi Reticulum
Major Site of new membrane synthsis in the cell
Rough ER synthsizes proteins
Smooth ER generates steroid hormones and sequesters Ca2+
Origin of Nuclear Membrane Formation
Membranes of ER, Golgi, endosomes, lysosomes are believed to have originated by invagination of the plasma membrane (expalins double membrane)
(NOT MITOCHONDRIA formed via endocytosis)
Sorting Signal
Unique AA sequence that tells synthesized protein where to go
No Sorting Signal = protein stay in cytoplasm
Nuclear Pore
Pores function as selective gates that actively transport specific macromolecules but allow free diffusion of smaller molecules
Nuclear Transport Receptor
Regulates access to nucleus
NTR binds to the nuclear localization signal of the incoming protein and helps orient the protein with the cystolic fibrils of the nuclear pore
Protein actively brought in via GTP hydrolysis
Signal Recognition Particle
SRP’s bind to growing polypeptide from free ribosome.
SRP shuttles ribsome, polypeptide to the ER
On the ER, Signal Recognition Particle Receptor binds to Signal Recognition particle and allows for the growing polypeptide to be shuttled into the ER
SRP’s slow down transation and allow the protein to reach destination first
Chaperones
Help proteins fold back into their proper conformation
Budding
Receptors binds to cargo
Clathrin binds to receptor/cargo complex with help of adaptin
Clathrin forms basket like strucutre
Dynamin pinches off the bud
Clathrin dissociates from the newly formed bud
Dynamin
Compound that squeezes off vessicle
Adaptin
Adaptor protein that allows clathrin to bind to the receptor once it has bound the appropriate cargo
v-SNARES
proteins found on the budding vessicle
t-SNARES
proteins found on the target surface (membrane, lysosome)
Lysosomes
Contains Hydrolytic enzymes and a H+ Pump
Mannos 6 phosphate = SRP for lysosome
Phagocytosis
Engulfing large paricles
Pinocytosis
Drinking cells
